PML designed these valve covers using original GM cast iron heads. Chevrolet Big block engines include: 396, 427, 454, and the 502.
These valve covers are taller than stock so check for space for larger valve covers.
Dimensions: Click here for dimensions. A separate window will open. Please check for clearance issues with firewalls, brake bosters, alternator, air conditioning brackets, and the like.
Finishes: Read about finishes and construction of PML parts.
These tall, heavy duty valve covers from PML for big block Chevy engines feature raised CHEVROLET script and fins and top quality construction. The classic CHEVROLET script is licensed from General Motors.
- Traditional design and sand cast aluminum construction for an old-school look and feel
- Taller than standard height and open interior to work with many roller rockers
- PCV and oil fill/breather holes
- Holes have internal baffles cast to reduce oil blow-by
- Thick walls and gasket flanges for strength and a secure seal to the cylinder head
Chevrolet big block engines include: 396, 427, 454, and the 502
These valve covers are a bit taller than stock to fit over many roller rockers. Always verify clearance before ordering. Using double gaskets to add height frequently causes leaks. Customers have reported to us that PML tall valve covers eliminated the need for double gaskets and the leaks.
For our standard height Chevy big block valve covers, see PML Part Number 9737.
General Motors Trademarks are used under license to PML, Inc.
Gaskets are not included with these valve covers. PML designed these Chevy Big Block valve covers to work with cork composite gaskets.
Breather and PCV Holes
PML Chevy big block valve covers have PCV and oil fill/breather holes and baffles cast into the covers. The internal baffles help prevent oil blow-by out the PCV and breather holes.
These holes work with standard 1 1/4 inch grommets.
If desired, a breather cap with a 1 inch outer diameter tube can be used with the breather grommet.
Click for dimension. A separate window or tab will open.
Engine configurations vary so please check for clearance for larger valve covers. The walls and gasket flange are thicker than stock and the fins and script add height to the top.
Look for clearance on the inside also, especially if you have roller rockers. A simple check can be made if you have the stock valve cover. Set the stock cover on the head and measure the distance, if any, between the gasket flange surface and the head. This cover is approximately 3/8 to 1/2 inch taller than the stock cover. PML tall covers are approximately 3/8 inch taller than our standard height covers.
Some customers have reported that their roller rockers contact the inside of these PML valve covers at corners. PML has heard that grinding a bit off the roller rockers on #1 intake and #6 intake, one intake rocker on each side of engine, can add enough clearance (but this is not something we have tried or endorse).
Inside of Valve Covers
These valve covers have an open interior without oil drippers so that there is clearance for many roller rocker systems.
The baffle is cast into the covers. (It is the square feature between the bolt holes.)
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Click to view or print PML Big Block Valve Covers PDF Flyer. A separate window will open and load the pdf file.